duete; see due, ty 2 ]. syn: duty, obligation refer to something a person feels bound to do. A duty often applies to what a person performs in fulfillment of the permanent dictates of conscience, piety, right, or law: one's duty to tell the truth; a parent's duty to raise children properly.
Mutations in the RB1 gene are responsible for most cases of retinoblastoma. RB1 is a tumor suppressor gene, which means that it normally regulates cell growth and keeps cells from dividing too rapidly or in an uncontrolled way.
Because retinoblastoma mostly affects infants and small children, symptoms are rare. Signs you may notice include: 1  A white color in the center circle of the eye (pupil) when light is shone in the eye, such as when taking a flash photograph.  Eyes that appear to be looking in different directions.